318 research outputs found

    Assessing material densities by vibration analysis and independent component analysis

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    The aim of this study was to investigate vibration analysis and independent component analysis (ICA) to assess the density of multiple materials making up a single structure. Density is important as it reveals information about physical properties of materials. The density of a single material can be determined from the relationship between its mass and volume. However, when a structure consists of multiple materials, identification of their individual densities from the structure is complicated. Vibration analysis is a technique that reveals information about an object’s physical properties such as its density. The investigation was carried out using a plastic test tube filled separately with three liquids of known densities; water, Chloroform and Methanol. Vibration was inducted into the tube, through an electronic system that produced a single impact at a predefined location on the tube. The resulting vibration signals were recorded using two vibration sensors placed on the tube. A signal source separation technique called ICA was used to obtain the vibration effects of the liquid and the tube. The power spectral densities (PSD) of ICA extracted vibration signals were examined. The frequency of the largest peak in the PSD was related to the liquid’s density under test. The study indicated that vibration analysis may be effective in assessing materials’ densities in a structure that contains multiple materials, however a larger study is needed to explore the findings

    An annotated checklist of the birds of the Tanimbar Islands

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    Wallacea, after years of seeming ornithological neglect, has recently come to the fore (see White & Bruce 1986, Coates & Bishop 1997). Since about 1981 there has been an increasing number of bird watchers and expeditions to the region resulting in the rediscovery of a number of 'feared extinct' and little known species. Most of the islands or island groups have by now received at least a cursory visit during the last 17 years. As a result many species previously known only from collections have been rediscovered, and others thought to be threatened have, thankfully, been shown not to be (see Coates & Bishop 1997). One of, the few exceptions to this coverage is the Tanimbar Islands

    Exploiting No-Regret Algorithms in System Design

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    We investigate a repeated two-player zero-sum game setting where the column player is also a designer of the system, and has full control on the design of the payoff matrix. In addition, the row player uses a no-regret algorithm to efficiently learn how to adapt their strategy to the column player's behaviour over time in order to achieve good total payoff. The goal of the column player is to guide her opponent to pick a mixed strategy which is favourable for the system designer. Therefore, she needs to: (i) design an appropriate payoff matrix AA whose unique minimax solution contains the desired mixed strategy of the row player; and (ii) strategically interact with the row player during a sequence of plays in order to guide her opponent to converge to that desired behaviour. To design such a payoff matrix, we propose a novel solution that provably has a unique minimax solution with the desired behaviour. We also investigate a relaxation of this problem where uniqueness is not required, but all the minimax solutions have the same mixed strategy for the row player. Finally, we propose a new game playing algorithm for the system designer and prove that it can guide the row player, who may play a \emph{stable} no-regret algorithm, to converge to a minimax solution

    Clover Trapping Mule Deer in Northwest Montana: Lessons Learned in a Unique Environment

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    Mule deer (Odocoileus hemionus) populations are in decline in many parts of western Montana, and in 2017, harvest in Montana Fish Wildlife and Parks (MFWP) management region 1 (R1) reached an all-time low. This prompts a need to better understand mule deer habitat selection behaviors in a range of ecosystems. Using resource selection functions (RSFs), we will compare how GPS-collared mule deer select nutritional resources and hiding cover at large scales (home range level) and fine scales (within-home ranges) relative to forage quality in 3 distinct ecosystems throughout western Montana. In February of 2017, we successfully captured 30 mule deer does along the Rocky Mountain Front using helicopternet-gunning, but were unsuccessful in the Whitefish Range and Fisher River drainage of R1 due to dense canopy cover. From December 2017 to present, we have relied on a crew of graduate students, MFWP game wardens and biologists, technicians, volunteers, and private citizens to scout for and clover-trap mule deer in R1. Here we present our capture success rate thus far, though trapping efforts are ongoing. We wish highlight how creative methods and recruitment of help from across a state agency can be pooled to initiate rigorous research in a thickly forested environment on a scarcely seen ungulate

    Genetic Analysis of Reproductive Traits and Antibody Response in PRRS Infected Sows

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    The genetic components of reproductive performance and antibody response of 641 commercial sows were assessed in a commercial herd that faced a PRRS outbreak. Antibody response after the PRRS outbreak was highly heritable and had high genetic correlations with reproductive traits. Many genomic regions were associated with antibody response in this study. These results indicate that there is a significant genomic component associated with PRRS antibody response and its high genetic correlations with reproductive traits during PRRS suggest that this trait could be used as an indicator trait to reduce the impact of PRRS on reproductive performance

    Effect of vitamin D supplementation on free and total vitamin D: A comparison of Asians and Caucasians

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    ObjectivesIt is well established that UK Asians typically have lower vitamin D levels than Caucasians. It is also known that vitamin D binding protein (DBP) is lower in some races than Caucasians. To investigate how ethnicity, skin colour and genetic variation affect the response to vitamin D (15000 IU) administered to young Asian and Caucasian men.DesignProspective, single?centre clinical trial.ParticipantsSixty young men (18?25 year) of Asian (n = 30) and Caucasian (n = 30) origin.MeasurementsWe measured serum calcium, phosphate, magnesium, alkaline phosphatase, albumin, parathyroid hormone; total 25 hydroxyvitamin D (25OHD); calculated and directly measured free 25OHD; DBP at baseline and 4 weeks; DBP genotype, skin colour (Fitzpatrick scale), dietary vitamin D and calcium intake at baseline; and urine calcium:creatinine ratio at baseline, 1 and 4 weeks.ResultsAt baseline, Asians had lower serum total 25OHD (26.4 [13.7] vs 34.1 [12.3] nmol/L P = 0.0272) and DBP (6.7 [3.4] vs 9.6 [4.4] nmol/L; P = 0.0065) but similar free 25OHD (16.7 [10.4] vs 17.8 [7.5] pmol/L P = 0.6530). After dosing, total 25OHD rose similarly in each group (?56 nmol/L), but measured free 25OHD rose more in Asians (18.1 [9.4] vs 12.2 [13.3] pmol/L P = 0.0464). Lower DBP at baseline, possibly reflecting genotype differences, was associated with a greater change in measured free 25OHD in Caucasians, but not in Asians.ConclusionsAsian compared with Caucasian males had a larger increment in measured free 25OHD following 150 000 units vitamin D3, possibly reflecting differences in DBP affinity for 25OHD. Ethnicity should be considered when devising guidelines for the treatment of vitamin D deficiency

    Aluminum exposure from parenteral nutrition in preterm infants: bone health at 15-year follow-up

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    Background: Aluminum has known neurotoxicity and may impair short-term bone health. In a randomised trial we showed reduced neurodevelopmental scores in preterm infants previously exposed to aluminum from parenteral nutrition solutions. Here, in the same cohort, we test the hypothesis that neonatal aluminum exposure also adversely affects long-term bone health, as indicated by reduced bone mass. Methods: Bone area (BA) and bone mineral content (BMC) of lumbar spine, hip and whole body were measured with Dual X-ray Absorptiometry (DXA) in 13-15yr olds who were born preterm and randomly assigned standard or aluminum-depleted parenteral nutrition (PN) solutions during the neonatal period. Results: 59 subjects (32% of survivors) were followed. Those randomised to standard PN solution had lower lumbar spine BMC; apparently explained by a concomitant decrease in bone size. In non-randomised analyses, subjects exposed to neonatal aluminum intakes above the median (55mcg/kg) had lower hip BMC (by 7.6% (95% CI 0.21 to 2.38; p=0.02)), independent of bone (or body) size. Conclusion: Neonates exposed to parenteral aluminum may have reduced lumbar spine and hip bone mass during adolescence, potential risk factors for later osteoporosis and hip fracture. These findings need confirmation in larger, more detailed studies. Nevertheless, given our previous finding of adverse developmental outcome in these subjects, and the sizeable number of contemporary infants undergoing intensive neonatal care who are still exposed to aluminum via parenteral feeding solutions, the potential adverse long term consequences of early aluminum exposure now deserve renewed attention
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